We are doing opensta script for mail sending from browser.I compose a mail and attach 20 kb excel file along with mail and send mail.This is the scenario.

I did script validation and run the script in modeller and checked in inbox iam getting the mail but the attachment is 1 kb.I opened the attached file there was no content

Please help me fix the above problem

Secondly when while recording the above scenario attaching file size of 1MB and send mail.
when i stopped recording script modeller hangs and i have to kill the process.

Please help regarding the above two problems.